Breaking 100Mbps on Multicast with WDS

I'm building WDS (with MDT) servers that will be replacing legacy Symantec Ghost imaging environments.

I really like the "Auto-cast" concept of a revolving multicast. That could really be game-changing.

However, all my servers refuse to go past the 100Mbps seemingly artificial limit. This has been seen on various HP, Dell, and VMWare servers running Windows Server 2008 R2, 2012, and 2012 R2.

For the most part, the transmission stays pegged at 99.9-100Mbps, occasionally suffering a drop to lower speeds, and then jumping back up. 

A Ghostcast on the other hand will jump from 30Mb to 300Mb wildly.

The network is full Gig, all gig ports, and all switches with IGMP(v3) support and snooping set up.

What can I do to unlock full Gig multicast speeds? Even a jump from 100Mb to 500Mb will be a huge jump.

I am multicasting to SSD devices and modern machines- I do not believe that disk I/O on the target device is a problem. Server I/O is on a RAID 5 or greater.

Thanks for any help...!

March 18th, 2014 8:02pm

Most NICs will default to auto-negotiate. On the server's NIC properties in Device Manager, on the Advanced tab, manually set the Link Speed & Duplex setting.
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March 19th, 2014 2:40pm

The main server in question has a full 1Gb connection, tested working by copying a large file to our NAS at 500Mb plus speeds.

I did look at setting the Link Speed & Duplex, however it has a Broadcomm card that only allows you to use Auto to use Gigabit. Reference here: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00805058&cc=us&dlc=en&lc=en

I'll switch that setting on some of my other servers with different cards, both virtual and physical. I'd hate to move away from Auto but I can guarantee it'll always be a gigabit uplink.

March 19th, 2014 3:32pm

I just did a deployment test and did not see any sort of cap being enforced. I had seen over 50% on the monitor for 1Gbps.

If you look at your WDS Server properties, on the Multicast tab, have you tried playing with the Transfer settings?

If your network does not have Link Aggregation enabled on the server's NIC and also your switches, it is possible for 100Mbps clients to drop the speed of the entire network down to 100Mbps even for gigabit interfaces.

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March 20th, 2014 2:10pm

Hello,

I want  to confirm if the issue has been resolved.

Any question please feel free to let us know.

March 24th, 2014 7:16am

In 2012 and 2012 R2, we did try the various transfer settings (one speed, two speeds, three speeds). We even saw the divergence once.

It seems in this version the Network profile is unselectable as it is auto-set. I am glad to hear you don't see a 100Mbit cap. Perhaps my Broadcomm network cards are an issue, though I do have one that does show 1000Mbit Full rather than forcing Auto.

On the switch side, I may force Gig-only. We are going to move to a newer VMWare platform, so hopefully those NICs will play well with WDS.

I believe WDS is just not auto-configuring with my NICs. I guess I'd feel a lot better if I could click the 1000Mbit button under Network rather than trust autoconfig, but that seems to no longer be an option.

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March 24th, 2014 12:58pm

Hi,

Notice: Content referred modifying registry, please backup before any operation.

The setting is also available via registry setting. In order to make sure the settings are applied, we ca have atry.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WDSServer\Providers\WDSMC

Change the value of "DefaultProfile" to the desired setting (10Mbps, 100Mbps, 1Gbps, or Custom).

If using Custom, make sure to make the necessary customizations under the registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WDSServer\Providers\WDSMC\Profiles\Custom

Do not make any customizations to any of the built in profiles (10Mbps, 100Mbps, 1Gbps). Use the Custom profile if any customizations are desired.

Hope this helps.

March 26th, 2014 10:48am

Hi Tripredacus

If I am reading your post correctly, are you seeing 50% network utilization when you multicast from a 1 GB server to 1GB clients? I seem to only be achieving 11%-14%. Here is a link to the thread I opened regarding my issue.

-Tony

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April 15th, 2015 11:00pm

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